The present invention generally relates to microelectronic devices. More particularly, the present invention relates to microelectronic devices suitable for regulating power.
Regulators are often employed to provide a desired, regulated power to microelectronic devices such as microprocessors. For example, switching regulators such as buck regulators are often used to step down a voltage (e.g., from about 3.3 volts) and provide suitable power to a microprocessor (e.g., about 10-30 amps and about 2-3 volts).
To increase speed and reduce costs associated with microprocessors, microprocessor gate counts and integration generally increase, while the size of the microprocessor per gate generally decreases. As gate counts, speed, and integration of microprocessors increase, supplying requisite power to microprocessors becomes increasingly problematic. For example, a current required to drive the processors generally increases as the number of processor gates increases. Moreover, as the gate count increases per surface area of a processor, the operating voltage of the processor must typically decrease to, among other reasons, reduce overall power consumption of the processor. Furthermore, as the microprocessor speed increases, the microprocessors demand the higher current at faster speeds.
Although buck regulators are generally suitable for controlling power to some microprocessors, such regulators are not well suited to supply relatively high current (e.g., greater than about 30 amps) at relatively high speed (e.g., greater than about 500 MHz.). One reason that buck regulators have difficulty supplying high current at high speed to the microprocessor is that the current supplied from the regulator to the processor has to travel a conductive path that generally includes a portion of a printed circuit board that couples the processor to the regulator. The relatively long conductive path between the processor and the regulator slows a speed at which the regulator is able to supply current to the processor. In addition, as microprocessor speed and current demands increase, the buck controller simply cannot provide the desired amount of current at the desired rate.
Yet another problem with buck regulators is that they are generally configured to supply power to within about xc2x15% of a desired value. While this range may be acceptable for processors running at relatively low currents, this range becomes decreasingly acceptable as the current requirements of microprocessors increase. Thus, as microprocessor gate counts and clock speeds increase, improved methods and apparatus for supplying high current at high speed and low voltage are desired. Furthermore, methods and apparatus for supplying the relatively high current within a relatively tight tolerance is desired.
The present invention provides improved apparatus and techniques for providing regulated power to a microelectronic device. More particularly, the invention provides improved devices and methods suitable for supplying electronic devices with relatively high, regulated current at relatively high speed.
The way in which the present invention addresses the deficiencies of now-known regulators and power supply systems is discussed in greater detail below. However, in general, the present invention provides an array of power regulators that provides power to a single microelectronic device.
In accordance with one exemplary embodiment of the present invention, an array of regulators is configured to provide power to a microprocessor. In accordance with one aspect of this embodiment, the array is formed as an integrated circuit on a semiconductor substrate. In accordance with a further aspect of this embodiment, the circuit is coupled to the microprocessor through a relatively short conductive path (e.g., by coupling the circuit to the device via bump interconnects). In accordance with yet a further aspect of this embodiment, the array circuit is formed on a silicon germanium (SiGe) substrate to facilitate faster current supply to the device. In accordance with a further exemplary embodiment of the present invention, a tiered power regulation system is configured to provide power to a microelectronic device. The tiered system includes at least two levels of power regulation. In accordance with an exemplary aspect of this embodiment, a first level of power regulation includes a switching regulator and a second level of regulation includes a linear regulator. In accordance with a further aspect of this embodiment, the second level of regulation includes an array of linear regulators.